Organizers of a two-day running relay along U.S. 1 on Friday and Saturday have agreed to a set of rules that Monroe County sheriff's officials are hoping will make the event run more smoothly this year.

Last year, Monroe County commissioners and sheriff's officials received dozens of angry calls from residents complaining about the Ragnar Relay, a 200-mile relay from Miami to Key West that backed up traffic on U.S. 1 for miles, and hours.

The relay teams' support vans, often driving alongside runners on the two-lane highway, caused traffic jams by slowing down to cheer on and talk with runners.

At a meeting following the relay, county commissioners relayed the residents' frustrations about the traffic to sheriff's and county staff.

Commissioners discussed not allowing the relay to take place again.

The annual event is scheduled during one of the Keys' busiest times, as both tourists and winter residents generally arrive in late December and early January.

Both sides have been in discussions about how race organizers could ensure a better flow of traffic.

The Sheriff's Office proposed, and relay organizers agreed to, disqualifying runners if their support teams slow down to talk with participants or back up traffic. The organizers also put together a driver training video.

"The vans should keep moving. They should not be stopping," said Alex Moulchin, a spokeswoman for the relay. "We understand traffic is an issue and we are trying to keep it to a minimum."

Also, the Sheriff's Office will have 17 extra deputies and two motorcycle units working Saturday in the Lower Keys and will be posting deputies at the transition stations to make sure traffic is not being slowed and runners are not crossing the highway, sheriff's Capt. Gene Thompson said.

"They know we are serious, and they are being serious as well," Thompson said.

There will be 500 teams with 10 runners each, Moulchin said. The relay starts at 5:30 a.m. Friday in Coconut Grove and ends Saturday at the Southernmost Hotel. Participants will run both day and night.

Traffic on U.S. 1 will be impacted again the following Saturday, as the Lower Keys will play host to its first-ever Iron Man Triathlon, which will have 1,000 participants.

The bike course of the race takes riders from Higgs Beach in Key West to the Middle Torch Keys. The Sheriff's Office will be placing messages on the electric signs throughout the Keys, warning motorists about traffic.